Seasonal prediction of the northern and southern temperature modes of the East Asian winter monsoon: the importance of the Arctic sea ice

2020 ◽  
Vol 54 (7-8) ◽  
pp. 3583-3597
Author(s):  
Peng Zhang ◽  
Zhiwei Wu ◽  
Jianping Li ◽  
Ziniu Xiao
Keyword(s):  
Sea Ice ◽  
East Asian Winter Monsoon ◽  
East Asian ◽  
Seasonal Prediction ◽  
Winter Monsoon ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Asian Winter Monsoon ◽  
Arctic Sea

scholarly journals Erratum to: Interannual variations of the dominant modes of East Asian winter monsoon and possible links to Arctic sea ice

2016 ◽  
Vol 48 (9-10) ◽  
pp. 3455-3455
Author(s):  
Chenghu Sun ◽  
Song Yang ◽  
Weijing Li ◽  
Ruonan Zhang ◽  
Renguang Wu
Keyword(s):  
Sea Ice ◽  
East Asian Winter Monsoon ◽  
East Asian ◽  
Winter Monsoon ◽  
Arctic Sea Ice ◽  
Interannual Variations ◽  
Asian Winter Monsoon ◽  
Arctic Sea

Interannual variations of the dominant modes of East Asian winter monsoon and possible links to Arctic sea ice

2015 ◽  
Vol 47 (1-2) ◽  
pp. 481-496 ◽  
Author(s):  
Chenghu Sun ◽  
Song Yang ◽  
Weijing Li ◽  
Ruonan Zhang ◽  
Renguang Wu
Keyword(s):  
Sea Ice ◽  
East Asian Winter Monsoon ◽  
East Asian ◽  
Winter Monsoon ◽  
Arctic Sea Ice ◽  
Interannual Variations ◽  
Asian Winter Monsoon ◽  
Arctic Sea

scholarly journals Impacts of Autumn Arctic Sea Ice Concentration Changes on the East Asian Winter Monsoon Variability

2014 ◽  
Vol 27 (14) ◽  
pp. 5433-5450 ◽  
Author(s):  
Zhang Chen ◽  
Renguang Wu ◽  
Wen Chen
Keyword(s):  
East Asian Winter Monsoon ◽  
East Asian ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Interannual Time Scale ◽  
Sea Ice Concentration ◽  
Asian Winter Monsoon ◽  
Arctic Sea ◽  
Ice Concentration ◽  
Western Arctic

Abstract The present study investigated the impacts of autumn Arctic sea ice concentration (SIC) changes on the East Asian winter monsoon (EAWM) and associated climate and circulation on the interannual time scale. It is found that the Arctic SIC anomalies have little impact on the southern mode of EAWM, but the northern mode is significantly associated with both western and eastern Arctic SIC anomalies. When there is less (more) SIC in eastern (western) Arctic, the EAWM tends to be stronger. The concurrent surface air temperature anomalies are induced both locally due to the direct effect of ice cover and in remote regions through anomalous wind advection. Analysis showed that eastern Arctic SIC anomalies have a larger effect on local atmospheric stability of the lower troposphere than western Arctic SIC anomalies. Winter temperature over the midlatitudes of East Asia is lower when there is more (less) SIC in the western (eastern) Arctic. The atmospheric response to the Arctic SIC anomalies is dominantly barotropic in autumn, and changes to baroclinic over the midlatitudes of Asia, but remains barotropic in other regions in winter. The mid- to high-latitude circulation systems, including the Siberian high, the East Asian trough, and the East Asian westerly jet stream, play important roles in connecting autumn Arctic SIC anomalies and the northern mode of the EAWM variability. No obvious concurrent sea surface temperature anomalies accompany Arctic SIC variations on the interannual time scale, indicating that the Arctic SIC anomalies have independent impacts on the East Asian winter climate.

scholarly journals On the Strengthened Relationship between the East Asian Winter Monsoon and Arctic Oscillation: A Comparison of 1950–70 and 1983–2012

2014 ◽  
Vol 27 (13) ◽  
pp. 5075-5091 ◽  
Author(s):  
Fei Li ◽  
Huijun Wang ◽  
Yongqi Gao
Keyword(s):  
Arctic Oscillation ◽  
East Asian Winter Monsoon ◽  
East Asian ◽  
Winter Monsoon ◽  
Arctic Sea Ice ◽  
Northern Eurasia ◽  
Tropical Region ◽  
Horizontal Structure ◽  
Near Surface ◽  
Asian Winter Monsoon

In this paper, the authors use NCEP reanalysis and 40-yr ECMWF Re-Analysis (ERA-40) data to document the strengthened relationship between the East Asian winter monsoon (EAWM) and winter Arctic Oscillation (AO) on the interannual time scale with a comparison of 1950–70 and 1983–2012. Their connection was statistically insignificant during 1950–70, whereas it was statistically significant during 1983–2012. The latter significant connection might be attributed to the East Asian jet stream (EAJS) upstream extension: the EAJS signal is relatively confined to the western North Pacific before the 1970s, whereas it extends westward toward East Asia after the 1980s. This upstream extension leads to the rearrangement of eastward-propagating Rossby waves with a much wider horizontal structure, thereby bonding the EAWM and the AO. Furthermore, the authors present observational evidence and model simulations demonstrating that the reduction of autumn Arctic sea ice cover (ASIC) is responsible for the strengthened EAWM–AO relationship after the 1980s by producing the EAJS upstream extension. After the 1980s, a strong anticyclonic anomaly over the polar ocean and anomalous easterly advection over northern Eurasia are generated by the near-surface heating over the Barents–Kara (B–K) Seas caused by the reduction of ASIC. This further induces cold anomalies over northern Eurasia, altering the meridional temperature gradient between the midlatitude and tropical region and consequently leading to westward penetration of the EAJS.

scholarly journals A Dynamical Index for the East Asian Winter Monsoon

2010 ◽  
Vol 23 (15) ◽  
pp. 4255-4262 ◽  
Author(s):  
Yueqing Li ◽  
Song Yang
Keyword(s):  
East Asia ◽  
East Asian Winter Monsoon ◽  
East Asian ◽  
Winter Monsoon ◽  
The Arctic ◽  
Tropospheric Temperature ◽  
Physical Processes ◽  
Asian Winter Monsoon ◽  
Monsoon Index ◽  
Wind Shears

Abstract A new index measuring the East Asian winter monsoon is defined using the mean wind shears of upper-tropospheric zonal wind based on the belief that the physical processes of both higher and lower latitudes, and at both lower and upper troposphere, should be considered to depict the variability of monsoon. When the index is high (low), the westerly jet is strong (weak), the East Asian trough is deep (shallow), the Siberian high is strong (weak), and anomalous low-level northerlies (southerlies) prevail over East Asia. As a result, the surface and lower-tropospheric temperature over East Asia decreases (increases) and the cold surges over Southeast Asia and tropical western Pacific are more (less) active. The index, which exhibits distinct interannual variations, is also strongly correlated with the Arctic Oscillation and Niño-3.4 sea surface temperature (SST) index. Compared to previous indexes, this index takes into account more influencing factors and better elucidates the physical processes associated with monsoon, enhancing interpretations of the variability of monsoon and its effects on regional weather and climate. Furthermore, the monsoon index is significantly linked to antecedent tropical Pacific SST and is highly predictable in the NCEP Climate Forecast System, indicating the advantage of the index for operational predictions of monsoon.

scholarly journals Distinct Modes of the East Asian Winter Monsoon

2006 ◽  
Vol 134 (8) ◽  
pp. 2165-2179 ◽  
Author(s):  
Bingyi Wu ◽  
Renhe Zhang ◽  
Rosanne D’Arrigo
Keyword(s):  
East Asia ◽  
Atmospheric Circulation ◽  
East Asian Winter Monsoon ◽  
Southern Oscillation ◽  
East Asian ◽  
Winter Monsoon ◽  
The Arctic ◽  
East Asian Trough ◽  
Siberian High ◽  
Asian Winter Monsoon

Abstract Two distinct modes of the East Asian winter monsoon (EAWM) have been identified, and they correspond to real and imaginary parts of the leading mode of the EAWM, respectively. Analyses of these modes used the National Centers for Environment Prediction (NCEP) and National Center for Atmospheric Research (NCAR) monthly mean reanalysis datasets for the period 1968–2003, as well as the Southern Oscillation index (SOI), North Atlantic Oscillation index, and eastern equatorial Pacific sea surface temperature (SST) data. Results were obtained by resolving a complex Hermite matrix derived from 850-hPa anomalous wind fields, and determining the resulting modes’ associations with several climate variables. The first distinct mode (M1) is characterized by an anomalous meridional wind pattern over East Asia and the western North Pacific. Mode M1 is closely related to several features of the atmospheric circulation, including the Siberian high, East Asian trough, East Asian upper-tropospheric jet, and local Hadley circulation over East Asia. Thus, M1 reflects the traditional EAWM pattern revealed in previous studies. The second distinct EAWM mode (M2), which was not identified previously, displays dominant zonal wind anomalies over the same area. Mode M2 exhibits a closer relation than M1 to sea level pressure anomalies over the northwestern Pacific southeast of Japan and with the SOI and equatorial eastern Pacific SST. Unlike M1, M2 does not show coherent relationships with the Siberian high, East Asian trough, and East Asian upper-tropospheric jet. Since atmospheric circulation anomalies relevant to M2 exhibit a quasi-barotropic structure, its existence cannot simply be attributed to differential land–sea heating. El Niño events tend to occur in the negative phase of M1 and the positive phase of M2, both corresponding to a weakened EAWM. The Arctic Oscillation does not appear to impact the EAWM on interannual time scales. Although the spatial patterns for the two modes are very different, the two distinct modes are complementary, with the leading EAWM mode being a linear combination of the two. The results herein therefore demonstrate that a single EAWM index may be inappropriate for investigating and predicting the EAWM.

scholarly journals The Linkage between Upper-Level Jet Streams over East Asia and East Asian Winter Monsoon Variability

2015 ◽  
Vol 28 (22) ◽  
pp. 9013-9028 ◽  
Author(s):  
Xiao Luo ◽  
Yaocun Zhang
Keyword(s):  
East Asia ◽  
Barents Sea ◽  
East Asian Winter Monsoon ◽  
East Asian ◽  
Winter Monsoon ◽  
The Arctic ◽  
The Tibetan Plateau ◽  
East Asian Trough ◽  
Asian Winter Monsoon ◽  
Upper Level

Abstract This study investigates the linkage between East Asian winter monsoon (EAWM) variability and upper-level jets, with particular focus on the East Asian polar front jet (PJ) and its concurrent variation with the subtropical jet located to the south of the Tibetan Plateau (TSJ). The winter upper-level zonal wind variations over the Asian landmass (70°–120°E) are dominated by two principal modes (i.e., meridional displacement of the PJ and out-of-phase variation in the intensity of the TSJ and PJ) and they are closely linked to the EAWM northern mode and southern mode, respectively. Southward shifting of the PJ concurs with northwestward displacement of the Siberian high (SH), an enhanced northern East Asian trough, leading to cold winter in northern East Asia. Meanwhile the simultaneous TSJ intensification and PJ weakening is linked to an amplified SH, a southward shift of the Aleutian low (AL), a strengthened southern East Asian trough, and a wavelike anomaly pattern extending from western Barents Sea downstream to East Asia at the 500-hPa level. Equatorward shift of the PJ is associated with La Niña conditions in the tropics and sea ice anomalies over the Arctic. An intensified TSJ and weakened PJ are preceded by autumn warming over the central and eastern Pacific Ocean and are linked to circulation anomalies induced by the extensions of stationary Rossby waves, as well as synoptic-scale transient eddy activity anomalies. Therefore, a combination of external forcing and internal atmospheric dynamics plays a role in driving the variations of two leading EOFs, and there is potential for seasonal forecasting of both modes.

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